Viruses used to send online threats from the personal computers of two men in the Kansai region had the ability to spy on data in the terminals and steal keyboard entry information, it was learned Tuesday.

An anime director, 42, of Suita, Osaka Prefecture, and a 28-year-old unemployed man in Tsu were arrested by the Osaka and Mie prefectural police, on suspicion of sending mass murder and bomb threat messages. They have been released by prosecutors' offices after both police headquarters and prosecutors discovered the possibility that their computers were controlled remotely through viruses.

As the locations specified in the threats are close to the residences of the two men, the police believe somebody skillfully assumed the identities of the two men after obtaining their personal information, informed sources said.

According to computer experts, a program to remotely monitor and record information input into a computer using a keyboard is called a "keylogger". There have been cases using similar software in the past, including one in which the software was hidden in a terminal at an Internet cafe and was used to steal passwords of Internet banking users who input them to withdraw money.

The viruses in question are believed to have functioned in a similar way, the sources said.

An e-mail was sent from the computer of the anime director to the website of the Osaka municipal government, saying he would commit a mass murder at Otaroad in Nipponbashi, Osaka. Otaroad is the nickname of a shopping arcade in the Nipponbashi district, a mecca for anime fans.

In the case of the Tsu man arrested by the Mie prefectural police, the location of the bomb and arson threat was stated as Ise Grand Shrines in Mie Prefecture. The man reportedly told police he regularly browsed the Internet bulletin board to which his computer posted bomb and arson threats.

Considering the circumstances, the police headquarters of the two prefectures think the person or people who deployed the viruses used the personal information of the victims after monitoring e-mails and access records of various sites within their computers to pen the threats, the sources said.

Recognised very recently

Meanwhile, police have found the viruses used in both cases are new types that have only recently been encountered overseas.

The police strongly suspect the terminals were infected with the viruses after the two men downloaded free software from Internet sites, the sources said.

As the sites can be browsed freely, the police believe somebody scattered viruses indiscriminately; they have since been trying to find out whether there are other people whose computers are infected with similar viruses.

According to the sources, the anime director downloaded the software on July 29, the day the e-mail containing a mass murder threat was sent.

The Tsu man also downloaded image processing software immediately before the threat messages were posted on the bulletin board on September 10.

The police have found traces of the download on the men's computers.

Both of the viruses were unknown until summer this year and could not be detected by antivirus software, the sources explained.

The police believe the attacker or attackers did not specifically target the two men, but targeted an indefinite number of people, according to the sources.

Additionally, a bulletin board message expressing an intent to bomb the Kyoto-based game company Nintendo Co. was posted from the unemployed man's terminal, an investigative source said.

The message, posted on the evening of September 10, also said the man would ram the front entrance of Nintendo offices with a truck and then stab employees one after another. The messages of intent to attack the Ise Grand Shrines and Nintendo were posted from his computer on the same day. The Mie prefectural police believe his computer was remotely controlled by a third party.